This invention relates to machinery for processing compressible material, such as flour tortillas and other foodstuffs. Wheat flour tortillas, for example, present special problems in handling because of the physical characteristics of the materials from which they are formed and of the intermediate and end products. It is known that such products possess characteristics which make them difficult to process mechanically, and to partially surface cook the material from which they are made, being, as they are, resilient materials which tend to form into non-round configurations when flattened and to exhibit a "memory" for resuming a spherical configuration, in spite of the dough having been "tempered", i.e., allowed to rest to remove stresses which tend to make it resist being re-worked. In addition, as contrasted with corn dough tortillas, for example, wheat dough is a wetter, stickier material, presenting more difficult handling properties. In accordance with the teaching of the present invention, the effect of surface heating or cooking is to "set" the material so as to stabilize its shape in preparation for subsequent cooking operations, although, for a long time, these problems have tended to mandate against automating the process of manufacture of such materials.
Recently, there have been efforts to achieve such automation by the use of converging carrier belts, and by reciprocating, opposing, heated platens. In this connection, reference is made to U.S. Pat. No. 3,223,053 and U.S. Pat. No. 3,397,655. Such efforts, however, have not proved to be entirely satisfactory since they involve relatively complex and costly machinery, which does not permit production rates or uniformity of sufficiently high levels.
Accordingly, it is an object of the present invention to provide means for compression forming foodstuff materials.
It is another object of the present invention to provide such means that is structurally simple, reliable and inexpensive to build and operate.
Another object of this invention is to achieve the foregoing objectives in machinery particularly adapted for the processing of materials which desirably are surface heated during the compression phase.
Yet another object of the present invention is to achieve the foregoing objectives in equipment for processing foodstuffs such as wheat "flour" tortillas and the like.